Finally got a handle on that weird voltage drop on old Zenith TV boards

For years I kept seeing these 1970s Zenith sets where the B+ voltage would sag under load, and everyone at the shop just said 'bad caps' and shotgun replaced the whole board. I started checking the solder joints on the flyback transformer pins specifically, and nine times out of ten, a cold joint there was the real culprit. A proper reflow with my Hakko 888D fixes it without touching a single capacitor. How many other 'known issues' are just one specific bad connection we've all been missing?

2 comments

2 Comments

jake_kelly241mo agoTop Commenter

Wait, you used to think it was just bad caps too?

ivan8731mo ago

Yeah, I replaced three caps before realizing.